A penguin’s day at sea – The Wellington edition

A penguin’s day at sea – The Wellington edition

Every year, Te Papa hosts a number of research interns, and this year we’ve very lucky to have Caroline Bost working with us in the Natural History research group. She’s a young researcher from France who’s working on penguin biology. Over the next few months she’ll be unpicking some of the mysteries of the elusive, yet remarkably ubiquitous little penguin Eudyptula minor (aka little blue penguin, blue penguin, fairy penguin) that nests around most of New Zealand’s mainland shores in small numbers. They’re listed as “At Risk – Declining” by Department of Conservation in their latest threat ranking.

In the early spring, the penguins begin preparing nests, accompanied by much of their characteristic growling and other noisy activity. One of their endearing attributes is the ability to make their home in any chink of protected woody or stony structure around the coast, including under wharves and houses – perhaps out of desperation to find suitable habitat in the wild, with many coastal areas that would have traditionally been used by the penguins for breeding now transformed into car-parking, sea walls and recreation areas. Various community projects are doing a great job of improving their habitat, providing nest boxes, which help keep them safe from dogs, cats and other predators. For example, Places for Penguins group in Wellington has a number of boxes out around Wellington’s coastal bays, and a second project run by volunteers associated with Ornithological Society has nest boxes spread around the shores at Matiu / Somes I. While some 20 or so pairs of penguins nest around Wellington, many hundreds nest at Matiu / Somes I., which is predator free.

Caroline Bost writes about her project in Wellington:

I’m starting a research project to study the behaviour and foraging areas of little penguins in Cook Strait. I’m working here with Dr. Susan Waugh, Senior Curator Sciences, in collaboration with a French research laboratory (CEBC-CNRS) who work on penguins in other parts of the Southern Ocean. I’ve got a French-German biology and physiology background and also have fieldwork experience working on different penguin species. Last year I volunteered on a research program on the Crozet Islands – a very remote sub-Antarctic locality – to study the at sea distribution of rock-hopper penguin, the foraging activities of breeding and non-breeding king penguin and also the study of their thermoregulation at-sea (using bio-logging techniques).

Our little penguin research programme aims to deploy miniature satellite loggers on breeding birds to study their at-sea foraging behaviour and conservation on different sites in the Cook Strait area. We’ve started our work in Wellington Harbour and have begun the first tracking work in early October. We also want to study the same species on another site in Marlborough/Queen Charlotte Sound to compare the at-sea foraging strategies of the birds between two sites.

Location of the study (yellow pin) at Wellington, New Zealand. Image from GoogleEarth. Copyright Te Papa

What you’ve found out about the penguins so far

We’re actually using different bio-logging technologies. We firstly deploy Argos-loggers, which weigh around 25 g, and send a message to satellites about the location and activity of the bird that is carrying the logger. This technology allows real-time monitoring of the equipped bird, in fact we are able to follow their at sea foraging movements (tracking information are sent to satellites every time the bird comes to the surface during its swim at sea). Another type of logger used on penguins are GPS loggers. Equally small, this type of logger allows more detailed data to be collected, but data are only accessible when the bird comes ashore on the breeding colony to feed its chick or to take over incubating eggs from its partner. The logger records the GPS coordinates every time when the bird comes to the surface and gets a satellite contact, but the data need to be downloaded once the bird is back from sea.

Little penguin from wellington population forages in Palliser Bay (red track). Little penguin #1 trip 1 – 6 October 2014. Data are unfiltered and contain some locations with error, as the penguin is not likely to have crossed land during its trip. Image Caroline Bost. Copyright, Te Papa

So far, we have equipped 2 birds with Argos-logger: one of them (likely a male) got back to its nest so we retrieved the logger from the bird as it came ashore. We were amazed to see how far it travelled, for such a small bird (about 1 kg in weight). The day it was coming back through the mouth of Wellington Harbour, the ferries were cancelled due to rough seas! The little penguin seemed unperturbed and made it back to shore just after dusk, and weighed in 150 g heavier than when it left. We also put a logger on its partner (probably the female), and we have the first part of its trip (see map below). It seems that both of them went out of Wellington Harbour to forage, direction Palliser Bay.

Little penguin #2 foraging in Palliser Bay. New Zealand during its foraging trip from Wellington Harbour. Data are unfiltered and contain some locations with error, as the penguin is unlikely to have crossed land areas during its trip. Image: Caroline Bost. Copyright, Te Papa

We have also equipped one bird so far with a GPS logger during its incubation trip, but have to wait until it c0mes ashore to collect the information about its foraging area. During logger retrieval we also take some measurements to get information about the body mass gained during the foraging trip (we weigh the penguin before deploying the logger and also after retrieval), we also measure their bill and flipper to tell what the sex of the bird is. It’s really surprising to work on penguins nesting in a city, mostly close to roads or gardens and very different to the sites I worked at before. I really appreciate the contact with other people and the possibility to share fieldwork experiences.

It’s also very interesting to look at the differences between penguins nesting in natural and predator free areas in comparison to those nesting in nest-boxes or also in very surprising places here in the city, and to look at how they adapt their behavior to breed in the city.

Hi, I’ve checked with the experts and it seems that these particular loggers (Argos PTT) need to have the antenna exposed above the water surface in order to send out a location. So being eaten by a large shark (depredated) would result in a loss of signal. And penguin. Thankfully, by both good luck and good management all of the one’s we’re tracking have come back to their nests in one piece.

Isn’t this interesting? What a long way they swim for short periods. Even though you think their trips overland are an error it looks as if they are coming ashore in Palliser Bay (surely not Pegasus Bay as in the 2nd graph) – do you think this is just for a short rest? Can you tell how long they spend there?

Hi, thanks for picking up the error there. My Canterbury origins are sneaking out subliminally. The first bird was away for about 5 days, but we’re still doing detailed data grooming, so will know after that whether it really did go ashore, but I’d be surprised…more likely foraging close to the coast.